National Paints Polyurethane Thinner is a special solvent used with PU (polyurethane) paints and clear coats to adjust their viscosity for smooth application. It helps the coating spread evenly, improves flow and gloss finish, and prevents brush marks or spray defects like orange peel. Typically, a controlled amount (around 5–15%) is added depending on whether you’re using brush, roller, or spray, and it’s also used for cleaning tools after applying PU coatings.

This thinner is made from strong, fast-evaporating solvents, so it is highly flammable and should be used in well-ventilated areas with proper safety gear like gloves and masks. It’s important to use only the recommended quantity, because excess thinner can reduce durability, gloss, and protection of the polyurethane coating.